Question

When we place a glass prism in the path of a narrow beam of white light a spectrum is obtained. What happens when a second identical prism is placed in an inverted position with respect to the first prism? Draw a labelled ray diagram to illustrate it.

 

Answer 1

The first prism disperses white light into its seven constituent colours and forms the spectrum. The other inverted prism recombines all the seven colors and gives a white light.